12) 1- You mustn't
2-you must
3-needn't
4-must
5-needn't
13)The ostrich's wings are bigger than the pelican's
The ostrich has an longer neck than the pelican
The pelican's legs are shorter than the ostrich's
The ostrich's head is as small as the pelican's head
The ostrich's beak is not as long as the pelican's
The ostrich runs faster than the pelican
